Q&A: Why are temperatures so high across Europe?

Human-induced global warming is making heatwaves more intense

Europe is sweltering in yet another heatwave that is due to last until at least next weekend with temperatures set to exceed 40 degrees over vast areas.

It is part of a pattern of heatwaves occurring earlier in the year and into summer with increasing temperatures, while the climate crisis is intensifying extreme temperatures.

What are the characteristics of the latest hot spell?

A high pressure system called the Azores high, which usually sits off Spain, has grown larger and pushed farther north, bringing high temperatures to the UK, France and the Iberian Peninsula, and trapping a bubble of rapidly warming air, not unlike a pressure cooker.

READ MORE

Ireland is on the fringes of this, experiencing dry, warm conditions though temperatures here are less oppressive. It will cool here a little in the middle of the week, as colder air pushes down from the north, but temperatures will climb again over the weekend reaching the high 20s by Sunday, according to Met Éireann.

How hot will it get?

Scorching temperatures above 40 degrees will continue in western continental Europe over coming days, with a risk of “a hot plume” around July 17th.

Winds are expected to turn southerly, bringing hot air up from North Africa and the Sahara. At the end of the week temperatures will hit 40-45 degrees across France and Spain. As the heat persists across western Europe, temperatures in parts of central and eastern Mediterranean are also predicted to rise to about 10 degrees above normal, exceeding the 40-degree mark across Italy and into the Balkans.

The Portuguese government declared an eight-day state of alert on Friday due to a high risk of wildfires. Europe as a whole has just experienced its second warmest June on record.

In the UK the Met Office has issued an amber warning due to the conditions posing a potential risk to life. It said there was a strong chance of the hottest day of the year so far occurring, surpassing the 32.7 degrees recorded at Heathrow on June 17th. There is also a chance the all-time UK record could be beaten — 38.7 degrees recorded in Cambridge University Botanic Garden in July 2019.

The highest air temperature recorded in the Republic is 33.3 degrees at Kilkenny Castle in 1887, but Ireland has had its warmest years during the past decade.

What are the risks?

Heatstroke and dehydration are the main health risks, with young children and older people being most vulnerable. Extreme heat is a killer, and can hamper food supply and human productivity.

The best advice is to keep hydrated and to find shade where possible when UV rays are strongest, between 11am and 3pm. If you have vulnerable family, friends and neighbours, make sure they are aware of how they can keep themselves protected from the warm weather.

Will heatwaves get worse in the future?

Scientists are clear that human-caused global heating is making heatwaves more intense, more likely and longer lasting. With increasing accuracy, attribution science can determine whether and to what extent human-induced climate change plays a role in the magnitude and frequency of extreme weather events including heatwaves.

“When it comes to summer heat, climate change is a complete game-changer and has already turned what would once have been called exceptional heat into very frequent summer conditions,” according to climate scientist Dr Friederike Otto of Imperial College London. “Every heatwave we experience today has been made hotter because of the fossil fuels we have burned over the last decades in particular.”

Scientists reported in 2020 the likelihood of the UK experiencing deadly 40-degree temperatures for the first time was “rapidly accelerating” due to climate change — this is probably less likely in Ireland but temperatures in excess of 35 degrees are a distinct possibility.

Heatwaves are caused by weather patterns that produce persistent high pressure, cloud-free conditions and dry continental winds during summer.

“[But] climate change is intensifying these heatwaves as greenhouse gas increases raise temperatures and a warmer, more thirsty atmosphere dries out the soil, so that more of the sun’s energy is available to heat the ground rather than evaporating water,” explains Prof Richard Allan of the University of Reading.

The bottom line is urgent action to reduce emissions can significantly reduce occurrence of extreme high temperatures. Human activity is adding more greenhouse gases to the atmosphere every year and the heat-trapping effect of this will only level off when the world reaches net-zero emissions. — Additional reporting: Guardian